Chains for use in conveyor systems



April 14, 1964 D. M. KING 3,128,593

CHAINS FOR USE IN. CONVEYOR SYSTEMS Filed July 3.1, 1961 United StatesPatent 3,128,593 CHAINS FOR USE IN CONVEYOR SYSTEMS Donald Mayer King,Argyle Works, Stevenage, England Filed July 31, 1961, Ser. No. 128,225Claims priority, application Great Britain Aug. 3, 1960 5 Ciaims. ((31.535) This invention relates to chains for use in conveyor systems and isconcerned particularly with chains of the kind comprising a successionof so-called inner and outer links which are interconnected by means ofconnecting pins, each inner link being in the form of an elongatedclosed loop while each outer link comprises two link elements which aredisposed in spaced parallel relation so as to accommodate between themthe opposed end portions of the adjoining inner links.

It has been proposed to provide for a chain of the kind set forth aninner link comprising two complementary U or J shaped pieces which areappropriately butted together and Welded to produce a link in the formof a closed elongated loop, each such U or J shaped piece being formedfrom a flat metal strip so shaped as to incorporate in each longitudinaledge two lateral protrusions or bulges which are spaced apart, each suchprotrusion or bulge on one edge being disposed opposite one on the otherso that the strip will have two zones of increased width which onbending of the strip to the U or J shape will be located one in eachlimb opposite the other and in proximity to the bend. Up to the presentthe two shaped strips from which the requisite U or J shaped pieces areproduced have been produced by stamping from a metal sheet and it hashappened that as a result of the shearing which takes place during suchprocess the edges of the strips have been scratched or scored. Suchimperfections have been found to constitute stress raisers which tend tolead to cracks in the strips and thus to failure of the finished linkwhen in use.

It is an object of the invention to evolve an improved method ofproducing the shaped strips employed for producing each inner linkelement.

It may be mentioned here that instead of forming each inner link of twoshaped metal strips as outlined above it may be feasible to employ asingle shaped strip which would be the equivalent of two of theafore-mentioned strips arranged end to end so that by appropriatebending of such single strip at two points to produce a closed loop andby welding the abutting ends an inner link of the requisite form will beproduced.

According to the present invention it is proposed in the production ofan inner link for a chain of the kind referred to, to utilise a singleor two complementary shaped metal strips the or each such strip beingproduced by taking a plain rectangular or substantially rectangularmetal strip and pressing into the latter at selected points or zones,recesses such as will result in a localised lateral flow or outwarddisplacement of metal at such points or zones sufficient to producebulges or rounded protrusions at spaced points along the longitudinaledges of the finished strip, the location of such bulges or protrusionsbeing such that a finished link produced as a result of appropriatebending of a single shaped strip and welding of the abutting endsthereof or as a result of the butting and welding together of two shapedstrips bent to a U or J shape, will incorporate at or adjacent each endthereof a zone of increased width.

In order that the nature of the invention may be more fully understoodreference will now be made to the accompanying drawing in which:

FIGURE 1 is a perspective view of a metal strip to be employed in theproduction of an inner link element,

FIGURE 2 is a perspective view of the strip when finished,

FIGURE 3 shows sectional views on the lines AA, B-B, C-C of FIGURE 2,

FIGURE 4 is a perspective view of a complete inner link,

FIGURE 5 illustrates a modification.

Referring to the drawings there is shown in FIGURE 1 a plain rectangularmetal strip 10 which is to be employed in the production of an innerlink. In order to produce the required finished shape indicated inFIGURE 2, recesses 11 and 12 are pressed into each face of the stripthereby to cause a lateral fiow or outward displacement of metal such aswill result in the formation of the two lateral protrusions or bulges 13and 14 at each longitudinal edge of the strip 10. In the embodimentillustrated an oil groove 15 is also pressed into each face of the stripbut such an additional feature while being advantageous, is notabsolutely necessary. Subsequent to the formation of the strip asindicated in FIGURE 2 it will be bent to a U or substantially U shape sothat each limb of the U will incorporate a pair of protrusions or bulges13, 13 and 14, 14 respectively which will be aligned with those on theother limb.

In order to form a complete inner link two shaped strips of the formshown in FIGURE 2 and each bent to a U or a substantially U shape, willbe butted together open end to open end and welded to produce a closedelongated loop or link such as is illustrated in FIGURE 4 which whenviewed in side elevation will be of generally rectangular form but willhave adjacent each end thereof a portion of increased width due to theexistence of two round humps disposed one at the upper and the other atthe lower edge thereof.

Instead of forming an inner link of two shaped metal strips as indicatedabove it may be feasible to employ a single strip as indicated in FIGURE5. Such a strip, which would be substantially double the length of thestrip 10, Would as indicated at 16, have four appropriately spacedrecesses pressed into each face thereof, thereby to provide a single orone piece finished strip which would be equivalent in shape to two ofthe strips shown in FIGURE 2 butted end to end. Such a shaped singlestrip would be bent twice at appropriate points to produce asubstantially C shape whereafter the two ends would be butt weldedtogether to produce a closed loop or link element of substantially thesame form as that shown in FIGURE 4. It will be appreciated, however,that by adopting such a process the finished link will incorporate asingle weld as opposed to two in the link described with reference toFIGURES 1-4.

By forming the strips which are to be employed in the production ofinner links in the manner outlined above the possibility of there beingscratches or imperfections on the edges thereof will be obviated sinceno operation is performed on said edges and they will be left clean andunmarked in any way. Thus the possibility of introducing stress raiserssuch as will lead to cracks and thus to failure of the finished linkswill be avoided.

I claim:

1. A method of forming an inner link for a chain, comprising: locallycompressing a rectangular strip having parallel longitudinal edges at apair of spaced locations to form recesses of curved shape in the stripto cause bulging of the strips in the longitudinal edges at said spacedlocations along a curve substantially corresponding to the curvature ofthe recesses and bending said strip midway between the recesses to formtwo substantially parallel legs wherein the bulges are substantiallyaligned with one another in a direction transverse of the legs.

2. A method of forming an inner link of a chain in which the link isprovided with a portion of increased extent, the method comprising:locally forming recesses in a flat rectangular metal strip havingsubstantially straight edges at spaced locations in the strip to formbulges in the edges of the strip at the recesses and bending the stripwith the bulges formed therein into substantially U-shape whereby a pairof strips may be abutted in end relation and joined to form a link ofcontinuous extent.

3. A method of forming an inner link for a chain in which the link isprovided with a portion of increased extent, the method comprising:forming a rectangular strip having parallel longitudinal edges, locallycompressing the strips at a pair of spaced locations, to form recessesof elliptical shape on the strip to cause bulging of the strips in thelongitudinal edges at said spaced locations and bending the strip at alocation between the recesses to form a strip of substantially U-shapeand wherein the bulges are substantially symmetrically formed in thethusly formed U-shaped strip.

4. A method of forming a link for a chain, the method comprising:locally compressing a rectangular strip having parallel longitudinaledges and opposite ends at two pairs of spaced locations to formrecesses of elliptical shape in the strip to cause bulging of the stripsin the longitudinal edges at said spaced locations along a curvesubstantially corresponding to the curvature of the recesses, bendingsaid strip midway between each of the recesses of the pair thereof toform two substantially parallel legs wherein one of the legs includesthe ends of the strips in abutting relation and each of the bulges issubstantially aligned with another bulge in a direction transverse ofthe legs, and joining together said ends which abut one another to forma closed link.

5. In a method of forming an inner link for a chain, comprising: locallycompressing a rectangular strip having parallel longitudinal edges at apair of spaced locations to form recesses of elliptical shape on thestrip to References Cited in the file of this patent UNITED STATESPATENTS 1,838,025 Waldron Dec. 22, 1931 FOREIGN PATENTS 860,177 GermanyDec. 18, 1952 869,746 Great Britain June 7, 1961

1. A METHOD OF FORMING AN INNER LINK FOR A CHAIN, COMPRISING: LOCALLYCOMPRESSING A RECTANGULAR STRIP HAVING PARALLEL LONGITUDINAL EDGES AT APAIR OF SPACED LOCATIONS TO FORM RECESSES OF CURVED SHAPE IN THE STRIPTO CAUSE BULGING OF THE STRIPS IN THE LONGITUDINAL EDGES AT SAID SPACEDLOCATIONS ALONG A CURVE SUBSTANTIALLY CORRESPONDING